20010126ebis/etat/ebuy/xdia Joint Effort1 20010126ebis/etat/ebuy/xdia Joint Effort2 Introduction...

20010126 ebis/etat/ebuy/xdia Joint Effort

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Introduction

• Extensible Markup language XML

• SCHEMA

• DTD


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What is a Schema?

•Schema:

A collection of statements that define the structure of a set of data as well as constraints on that structure.

•Schema language:A language used to define a schemasuch as the XML DTD language or an XML schema language.


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• XML - Extensible Markup Language

<?xml version=“1.0”?><USAddress> <name>”Alice Smith”</name> <street>”333 Huntington Ave”</street> <city>”Boston”</city> <state>”MA”</state> <zip>”02115”</zip></USAddress>


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<!DOCTYPE USAddress [<!ELEMENT USAddress(name, street, city, state, zip) ><!ELEMENT name (#PCDATA) ><!ELEMENT street (#PCDATA) ><!ELEMENT city (#PCDATA) ><!ELEMENT state (#PCDATA) ><!ELEMENT zip (#PCDATA) >]>

XML Schema - a specification of the synta x and semantics of XML documentsDTD - document type definition


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XML Query Languages

Traditional Way:• SQL•XML QL•Lore


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<Music> CD year =1193”> <group> Spyro Gyra </group>

<title>Dreams Beyond Control </Title> <track no=“1”>

<title>Walk the Walk</title><composer>Fernandez</composer>

</track><track no=“10”> <title>Same Difference</title> <composer>Becckenstein</composer> <composer>Fernandez</composer></track>

</cd> <score>

<title>Morning Dance</title><group>Spyro Gyra>/group><composer>Beckenstein</composer><guitar>C dim 7 …</guitar>

</score> </music>

•XML document for Music


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Querying XML in the Traditional Way

Lorel:1) select music.%

2) select music .% where music .%.group = “Spyro Gyra”


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Construct <score> { where <music> <score></score>> Element_AS $s </music> CONSTRUCT $s } </scores>and CONSTRUCT <favorite> { WHERE <music> <$a> <group>Spyro Gyra</group> </> </music> CONSRUCT $x} </favorite>

•XML QL


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•VISIUAL LANGUAGE FOR XML:

•XING Stands for

XML IN GRAPHIC


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What can Visual language contribute to XML

•Eliminating textual and structure representation of data.

•Querying of XML data can be accomplished VIA pattern.


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Criteria for XML VISUAL Language:

•Do not define textual query language•Use simple and intuitive visualizationof XML•Employ pattern matching•Keep the system as simple as possible


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CD

Year:1993title:Dream Beyond Controlgroup:Spyro Gyra

Track

No:1title: walk the walkcomposer:Fernande

No:10title:same differecomposer:Beckensicomposer :fernande

score

Title: morning dancegroup: spyro Gyracomposer:Beckensguitar:C dim 7

Visualization of music schema

XING


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XML and visual Language:

•Support for XML

•Visual Languages contribution

•XML contribution to visual language


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Visualization of XML:

•Well suited•Attractive•Can be easily exchanged between computer•Simple and interesting for end user


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Document Metaphore:

•Free text together with categorized information

•Field consist of header and value

•Patterns or rules


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Document Patterns:

• Patterns matching provides a light weight approach to data processing

•Desired data is described by samples or patterns

•Usually a patterns consist of constants and variables


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Construct <score> { where <music> <score></score>> Element_AS $s </music> CONSTRUCT $s } </scores>and CONSTRUCT <favorite> { WHERE <music> <$a> <group>Spyro Gyra</group> </> </music> CONSRUCT $x} </favorite>

music

SCORE

In XING all Scores can be foundby the above pattern.


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music

Group:Spyro gyra

music

CD

Group: Spyro Gyra

score

Group: Spyro Gyra

guitar:

CDs and guitar scores of favorite Group*


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music

o o *

Composer: Beckenstein

Deep Query:Is given by any pattern that is prefixed by an ellipsis,meaning to look for that pattern at any nestingdepth within the searched document.


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Document rule:

•Document rule can be used to reformat or re-structure query results.•Consist of two document patterns that are joined by a double arrow

P Q

•P is called the argument pattern

•Q is called result pattern


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Document Rules:

music

Piece {* }

group:Spyro Gyra

favorite

piece


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Document Rules:

music

0 0

*

composer:Beckenstein

list

Composertitle


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Conclusion

Bases on visual document metaphor and the notation of document pattern and rules, XING provides a direct and simpleway to locate and select informationin XML data resources.

Xing is usable by broad audience because the interface is completely independent froma complex, textual formal query language


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XML-GL

We introduce a data model for XML documents, called XML-GDM (XML Graphical Data Model), which we use to represent both the expected structure ofXML documents (i.e., their DTDs) and actual documents. The data model has a graphical representation: a syntax directed translation produces graphical schemasof DTDs or of documents. We envision a typical use of XML-GL in which users are presented with the graphical representation of the DTD and can producequeries in XML-GL with a WYSIWYG interface, with suitable drag and fill commands.


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The Requirements for an XML Query Language

XML is a recent recommendation of the World Wide Web Consortium for a meta-language to define markups for content publishing on the Web. Derived fromSGML, XML allows document producers to define and use the set of tags that best mirrors the structure and conceptual properties of the information they want topublish.

The use of XML will bring a major change in the structure of Web information, which will become more and more a collection of semistructured objects, i.e., piecesof content for which at least a partial representation of structure (known as schema in the database lexicon) is available.


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<!ELEMENT order (shipto, contact?, item+, date)> <!ATTLIST order number PCDATA #REQUIRED> <!ELEMENT shipto (fulladdress|reference)> <!ELEMENT contact (reference|PCDATA)> <!ELEMENT fulladdress (company, addressline+, city)> <!ELEMENT reference EMPTY> <!ATTLIST reference customer IDREF> <!ELEMENT person (firstname?,lastname,fulladdress)> <!ATTLIST person id ID> <!ELEMENT company PCDATA> <!ELEMENT addressline PCDATA> <!ELEMENT city PCDATA> <!ELEMENT date (day, month, year)> <!ELEMENT day PCDATA> <!ELEMENT month PCDATA> <!ELEMENT year PCDATA> <!ELEMENT item (book, quantity, discount?)>


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An XML-GL query consists of four parts:

1. The extract part identifies the target of the query, by indicating the target documents and the target elements inside these documents; by drawing a parallel2. The match part (optional) specifies logical conditions that the target elements must satisfy in order to be part of the query result. 3. The construct part specifies the structure of the result document; the same query can be formulated with different contruction parts, to obtain results formatted differently. 4. The clip part (optional) specifies the elements from the target documents to be retained in the constructed result.


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Besides the basic features shown by these examples, XML-GL addresses the remaining requirements by allowing:

String manipulation capabilities that enlarge the range of possible queries. The definition of the transitive closure of the containment and reference relationships.Arbitrary computation on document numeric content via built-in functions. The exploitation of element order in the documents. The use of equivalence rules on XML documents and/or XML-GL queries for defining similarity retrieval.


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Questions!

20010126ebis/etat/ebuy/xdia Joint Effort1 20010126ebis/etat/ebuy/xdia Joint Effort2 Introduction...

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